1. Field of the Invention
The present invention relates to a memory device for use as an auxiliary memory device in a numerical control apparatus for controlling a machine tool or the like, and more particularly to a portable auxiliary memory device employing a large-capacity and inexpensive magnetic recording disk.
2. Description of the Related Art
Numerical control (NC) apparatuses are used for controlling machine tools, industrial robots, and the like according to machining programs recorded on paper tapes and read one block by one block by the NC apparatus. As the machining process becomes more complex, the amount of information in the machining program increases, and cannot sometimes be recorded on a paper tape of an ordinary length. Large-capacity and relatively inexpensive magnetic recording disks or floppy disks, which are used in personal computers or the like, have recently found use as auxiliary memory devices for storing entire machining program information for an NC apparatus. A drive device for floppy disks is connected to the NC apparatus and combined with a CRT display, a keyboard, or a paper tape reader for use as the auxiliary memory device for the machines control unit of an NC apparatus.
Recently floppy disk drive devices have been incorporated in NC apparatus is proper. However since the drive devices are not portable, but contained in the NC apparatus, they cannot be used as auxiliary memory devices for other NC apparatus.